Spin-coating method, determination method for spin-coating condition and mask blank

ABSTRACT

A spin-coating method according to the present invention includes a uniforming step of rotating a substrate at a predetermined main rotation speed for a predetermined main rotation time so as to primarily make a resist film thickness uniform, and a subsequent drying step of rotating the substrate at a predetermined drying rotation speed for a predetermined drying rotation time so as to primarily dry the uniform resist film. In the present invention, a contour map, for example, of film thickness uniformity within an effective region (critical area) shown in FIG.  3 A is determined (generated), and resist-coating is performed by selecting a condition within the optimum region in this contour map in which the film thickness uniformity (within an effective region) can be the maximum, or within the region in which the film thickness uniformity (within an effective region) can be high enough for a desirably specified.

[0001] This application claims priority to prior application JP2002-101840, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a spin-coating method forspin-coating a substrate surface in the shape of a square or the likewith a resist film, a resist bottom anti-reflective coating (BARC), aresist top anti-reflective layer (TARL), a resist top protective film, aconductive film or the like (hereafter may be collectively referred toas a resist film) by a specific method. In particular, the presentinvention relates to a determination method for a resist spin-coatingcondition in order to make the coating thickness of the resist filmfurther uniform, and a resist spin-coating method, as well as aphotomask blank, etc., including a resist film, a resist bottomanti-reflective coating, a resist top anti-reflective layer, a resisttop protective film, a conductive film or the like, or a combinationthereof, formed by this method.

[0004] 2. Description of the Related Art

[0005] In spin coating of resist solution, a commonly used spin-coatingdevice has a basic configuration shown in FIG. 1. In FIG. 1, thespin-coating device comprises a nozzle 1 for supplying resist solution,a chuck 2 for chucking a substrate 3 and attached onto a cup 4, and amotor 5 for rotating the chuck 2 together with the substrate 3. As anexample of the spin-coating method using such a spin-coating device, thefollowing resist-coating method has been proposed (Japanese PatentPublication No. 4-29215). This resist-coating method aims to make thecoating film thickness uniform, especially regarding a square-like(square or rectangular) substrate. This resist-coating method iscomposed of a uniforming (evening or flatting) step and a subsequentdrying step. In the uniforming step, a substrate is rotated by selectinga setting rotation speed corresponding to a desirably specified filmthickness, a predetermined rotation time and a product of the settingrotation speed and the predetermined rotation time. In the drying step,the square-like (square or rectangular) substrate is rotated at therotation speed lower than the setting rotation speed in the uniformingstep, and thereby, the resist film is dried.

[0006] Regarding the above mentioned resist-coating method, inconsideration of the film thickness and the concentration (viscosity) ofthe resist solution, a setting value R of the rotation speed of thesquare-like (square or rectangular) substrate is specified to be apredetermined value (desirably 250 to 2,000 rpm) within the range of 100to 6,000 rpm in the uniforming step, a rotation time T is specified tobe 20 seconds or less after the rotation speed has reached the settingvalue R (the predetermined value), and the product (R×T) of the settingvalue R of the rotation speed and the rotation time T is specified to be24,000 (rpm×sec) or less. The rotation speed is experimentally specifiedto be 130 rpm or less in the drying step following the uniforming step.Furthermore, the vapor pressure (at 20° C.) of a solvent is specified tobe 20 mmHg or less, while the solvent adjusts the viscosity of theresist solution. By satisfying these conditions, protuberance (fringe:one or various light or dark bands produced by the interference of lightdue to the resist film thickness variation) of the resist film can bereduced outside the inscribed circle of the square-like (square orrectangular) substrate, and the region of uniform film thickness can beexpanded by reduction of this fringe.

[0007] However, the above mentioned resist-coating method merely limitsthe range of the combination (rotation condition) of the rotation speedand the rotation time in the uniforming step to the range inside thecurve Ca (the range diagonally shaded with solid lines) in FIG. 2, ormerely limits to the desirable range diagonally shaded with brokenlines. Consequently, the above mentioned resist-coating method does notpropose a technique for selecting the rotation condition to achievemaximum (the best) film thickness uniformity within an effective region(critical area) under the condition practically required in the abovementioned field of application, that is, with respect to a predeterminedresist species, a desirably specified film thickness and a desirablyspecified effective region.

[0008] The above mentioned resist-coating method merely specifies anupper limit with respect to selection of the rotation speed in thedrying step as well. Therefore, the above mentioned resist-coatingmethod does not propose a technique for selecting the rotation conditionto achieve maximum (the best) film thickness uniformity within aneffective region nor a technique for optimizing the drying rotationspeed.

[0009] Furthermore, the above mentioned resist-coating method merelyspecifies an upper limit of the vapor pressure of the solvent withrespect to a method for adjusting the concentration (viscosity) of theresist solution, and therefore, does not propose a technique foroptimizing the concentration of the resist solution.

[0010] For the reasons described above, conventionally, resist-coatingconditions were determined by trial and error within the range of thevalues of the above mentioned resist-coating method, and therefore, muchtime was required for achieving desirably specified film thicknessuniformity within an effective region.

[0011] In the conventional methods, a relative evaluation was able to beperformed between individual coating conditions with respect to the filmthickness uniformity within an effective region. However, it was notpossible to judge whether the determined condition (the rotation speedand the rotation time) is a limit value for the film thicknessuniformity within an effective region (that is, the optimum coatingcondition for achieving maximum film thickness uniformity within aneffective region). That is, conventional methods were not able toperform an absolute evaluation of the film thickness uniformity withinan effective region.

[0012] The resist concentration may significantly fluctuates relative toa specification value or a target value due to variations in themanufacture (variations in quality) of a resist solution (a coatingsolution) or variations in dilution for adjusting a viscosity. When theresist solution is applied while the resist concentration significantlyfluctuates, desirably specified film thickness uniformity within aneffective region cannot be achieved.

[0013] Regarding some resist species, the film thickness uniformitywithin an effective region is highly sensitive to the coating condition(the rotation speed and the rotation time) and the coating environment(ambient temperature and humidity), and therefore, desirably specifiedfilm thickness uniformity within an effective region cannot be achievedwhen these coating conditions fluctuate relative to the setting valuesdue to coating device factors and environmental factors.

[0014] Regarding some resist species, in order to achieve desirablyspecified film thickness uniformity within an effective region in a widerange of, for example, 3,000 to 5,000 angstroms or 3,000 to 4,000angstroms, conventional methods took much time because a coatingcondition was independently determined with respect to each resist filmthickness. In addition, many resist solutions having differentconcentrations (viscosities) had to be prepared, and a specific facility(a resist solution dispensing device including a filtration mechanismfor the solution) was required for each solution.

SUMMARY OF THE INVENTION

[0015] The present invention was made to overcome the above mentionedproblems. The present invention relates to a spin-coating method forapplying resist solution or other coating solution by a specificspin-coating method described above.

[0016] It is a major objective of the present invention to provide atechnique for optimizing a main rotation condition, a technique foroptimizing a drying rotation condition and a technique for optimizing aconcentration (viscosity) condition of resist solution or other coatingsolution, and to establish a technique for reliably (univocally)determining these optimum conditions without depending ontrial-and-error methods.

[0017] It is another objective of the present invention to provide atechnique capable of speedily, univocally determining the optimumspin-coating condition without depending on trial-and-error methods,even when a resist species or other coating solution is changed, adesirably specified effective region (critical area) is changed, adesirably specified film thickness is changed, and a spin-coating device(for example, the shape of a cup and the shape of a chuck) is changed.

[0018] It is another objective of the present invention to provide adetermination method for a resist spin-coating condition capable ofreliably (univocally) achieving desirably specified film thicknessuniformity within an effective region (in particular, maximum filmthickness uniformity within an effective region) in a desirablyspecified effective region without depending on trial-and-error methodsregarding a predetermined resist species or other coating solution, anda spin-coating method, as well as a mask blank (photomask blank) or asubstrate including a resist film, other film or the like, or acombination thereof, formed by this method.

[0019] It is another objective of the present invention to provide adetermination method for a spin-coating condition capable of reliably(univocally) achieving a desirably specified film thickness (mean) anddesirably specified film thickness uniformity within an effective regionin a desirably specified effective region without depending ontrial-and-error methods regarding a predetermined resist species orother coating solution, and a spin-coating method, as well as a maskblank (photomask blank) or a substrate including a resist film, otherfilm or the like, or a combination thereof, formed by this method.

[0020] It is another objective of the present invention to provide adetermination method for a spin-coating condition capable of reliablyachieving an optimum spin-coating condition in accordance with thecharacteristics of a resist species or other coating solution withoutdepending on trial-and-error methods, and a spin-coating method, as wellas a mask blank (photomask blank) or a substrate including a resistfilm, other film or the like, or a combination thereof, formed by thismethod.

[0021] It is another objective of the present invention to provide aspin-coating method capable of applying resist solution having oneconcentration or other coating solution having one concentration in sucha manner that plural sorts of resist film thickness or plural sorts ofcoating film thickness can be achieved while the film thicknessuniformity within an effective region is within a predetermined range.

[0022] In order to achieve the above mentioned objectives, the presentinvention can include various aspects described below.

[0023] The present invention is applied to a spin-coating methodincluding a uniforming (evening or flatting) step of dispensing resistsolution on a substrate and rotating the substrate at a predeterminedmain rotation speed for a predetermined main rotation time, so as toprimarily make the resist film thickness uniform, and a drying step ofrotating the substrate at a predetermined drying rotation speed for apredetermined drying rotation time after the uniforming step, so as toprimarily dry the uniform resist film.

[0024] First Aspect

[0025] In the first aspect of the present invention, a plurality ofsamples are prepared by being coated with the resist solution under aplurality of conditions resulting from independent, stepwise change inparameters in the uniforming step, while the parameters are the mainrotation speed and the main rotation time, and under the condition inwhich the concentration (viscosity) of the resist solution is fixed atan arbitrary concentration, and the drying rotation speed in the dryingstep is fixed at an arbitrary rotation speed. The resist filmthicknesses of each sample are measured at a plurality of points withina desirably specified effective region (critical area) in the substrate,and film thickness uniformity within an effective region is determinedfrom results of film thickness distribution [range (maximum minusminimum) value or standard deviation value], within the effective region(critical area) of the measurment. The relationship is therebydetermined between the condition of combination of the main rotationspeed and the main rotation time of each sample and the film thicknessuniformity within an effective region of each sample, and thisrelationship is specified to be reference data A. A condition I ofcombination of the main rotation speed and the main rotation time forachieving desirably specified film thickness uniformity within aneffective region is determined based on the reference data A, andresist-coating is performed in accordance with results of the conditionI of combination of the main rotation speed and the main rotation time.

[0026] Second Aspect

[0027] In the second aspect of the present invention, the reference dataA is a contour map in which the vertical axis indicates the mainrotation speed, the horizontal axis indicates the main rotation time,and points corresponding to the same film thickness uniformity withinthe effective region are bonded by a contour line, or a bird's eye viewdrawn by point-plotting while the X axis, the Y axis and the Z axisindicate the main rotation speed, the main rotation time and the filmthickness uniformity within the effective region, respectively.

[0028] Third Aspect

[0029] In the third aspect of the present invention, a plurality ofreference data A according to the above mentioned first aspect orcontour maps or bird's eye views according to the above mentioned secondaspect are determined based on stepwise change in the concentration(viscosity) of the resist solution. A condition II of concentration(viscosity)of the resist solution for achieving maximum (the best) filmthickness uniformity within the effective region is determined among thegroup consisting of the plural reference data A, the group consisting ofthe plural contour maps or the group consisting of the plural bird's eyeviews, and resist-coating is performed in accordance with results ofcondition II of concentration (viscosity) of the resist solution.

[0030] Fourth Aspect

[0031] In the fourth aspect of the present invention, a plurality ofreference data A according to the above mentioned first aspect orcontour maps or bird's eye views according to the above mentioned secondaspect are determined based on stepwise change in the drying rotationspeed in the drying step while the concentration (viscosity) of theresist solution is fixed at an arbitrary concentration. A condition IIIof drying rotation speed for achieving maximum film thickness uniformitywithin the effective region is determined among the group consisting ofresults of plural reference data A, the group consisting of results ofplural contour maps or the group consisting of results of plural bird'seye views, and resist-coating is performed in accordance with results ofcondition III of drying rotation speed.

[0032] Fifth Aspect

[0033] In the fifth aspect of the present invention, a plurality ofsamples are prepared by being coated with the resist solution under aplurality of conditions resulting from stepwise change in the dryingrotation speed in the drying step and under the condition in which themain rotation speed and the main rotation time in the uniforming stepare fixed at the condition I of the main rotation speed and the mainrotation time determined according to the above mentioned first aspect.The resist film thicknesses of each sample are measured at a pluralityof points within a desirably specified effective region in thesubstrate, and film thickness uniformity within the effective region isdetermined from results of film thickness distribution [range (maximumminus minimum) value or standard deviation value], within the effectiveregion (critical area) of the measurment. The relationship is therebydetermined between the drying rotation speed of each sample and the filmthickness uniformity within the effective region of each sample, andthis relationship is specified to be reference data B. A condition IV ofthe drying rotation speed for achieving maximum film thicknessuniformity within the effective region is determined based on thereference data B, and resist-coating is performed in accordance withresults of condition IV of the drying rotation speed.

[0034] Sixth Aspect

[0035] In the sixth aspect of the present invention, a plurality ofsamples are prepared by being coated with the resist solution under aplurality of conditions resulting from stepwise change in theconcentration (viscosity) of the resist solution and under the conditionin which the main rotation speed and the main rotation time in theuniforming step are fixed at the condition I of the main rotation speedand the main rotation time determined according to the above mentionedfirst aspect. The resist film thicknesses of each sample are measured ata plurality of points within a desirably specified effective region inthe substrate, and a mean value of results of resist film thicknesses isdetermined. The relationship is thereby determined between theconcentration (viscosity) of the resist solution of each sample and themean value of the resist film thicknesses of each sample, and thisrelationship is specified to be reference data C. A condition V ofconcentration (viscosity) of the resist solution for achieving adesirably specified mean resist film thickness is determined based onthe reference data C, and resist-coating is performed in accordance withresults of condition V of concentration (viscosity) of the resistsolution.

[0036] Seventh Aspect

[0037] In the seventh aspect of the present invention, a plurality ofsamples are prepared by being coated with the resist solution under aplurality of conditions resulting from stepwise change in theconcentration (viscosity) of the resist solution and under the conditionin which the main rotation speed and the main rotation time in theuniforming step are fixed at the condition I of the main rotation speedand the main rotation time determined according to the above mentionedfirst aspect, and the drying rotation speed in the drying step is fixedat the condition IV of the drying rotation speed determined according tothe above mentioned fifth aspect. The resist film thicknesses of eachsample are measured at a plurality of points within a desirablyspecified effective region in the substrate, and a mean value of resultsof resist film thicknesses is determined. The relationship is therebydetermined between the concentration (viscosity) of the resist solutionof each sample and the mean value of the resist film thicknesses of eachsample, and this relationship is specified to be reference data C′. Acondition V′ of concentration (viscosity) of the resist solution forachieving a desirably specified mean resist film thickness is determinedbased on the reference data C′, and resist-coating is performed inaccordance with results of condition of V′ of concentration (viscosity)of the resist solution.

[0038] Eighth Aspect

[0039] In the eighth aspect of the present invention, the main rotationspeed and the main rotation time are selectively fixed at the conditionI by the determination method for the main rotation condition accordingto the above mentioned first aspect or the above mentioned secondaspect. The drying rotation speed is selectively fixed at the conditionIV by the determination method for the drying rotation conditionaccording to the above mentioned fifth aspect. The concentration(viscosity) of the resist solution is selectively fixed at the conditionV′ by the determination method for the resist concentration (viscosity)according to the above mentioned seventh aspect. Subsequently,resist-coating is performed in accordance with the condition I,condition IV and condition V′.

[0040] Ninth Aspect

[0041] In the ninth aspect of the present invention, the condition IIIof drying rotation speed according to the above mentioned fourth aspectis determined from the group consisting of the plural reference data,the group consisting of the plural contour maps or the group consistingof the plural bird's eye views. At this time, the drying rotation speedcondition is selected in order that fluctuations in the film thicknessuniformity within the effective region becomes small and stable withrespect to fluctuations in the main rotation speed and/or the mainrotation time in a practical coating process relative to the settingvalues or with respect to fluctuations in the resist concentration(viscosity) for achieving the desirably specified mean resist filmthickness, and resist-coating is performed in accordance with results ofcondition.

[0042] Tenth Aspect

[0043] In the tenth aspect of the present invention, the condition IIIof drying rotation speed according to the above mentioned fourth aspectis determined from the group consisting of the plural reference data,the group consisting of the plural contour maps or the group consistingof the plural bird's eye views. At this time, the condition III ofdrying rotation speed is selected in order that when plural thicknessesof coatings are applied using the resist solution having the same resistconcentration (viscosity), the plural thicknesses of coatings can beapplied while the film thickness uniformity within the effective regionis within a constant range, and resist-coating is performed inaccordance with results of condition III, so as to achieve a pluralityof thicknesses.

[0044] Eleventh Aspect

[0045] In the eleventh aspect of the present invention, the substrate isa square-like (square or rectangular) substrate in any one of the abovementioned first to tenth aspects.

[0046] Twelfth Aspect

[0047] In the twelfth aspect of the present invention, the spin-coatingcondition is determined based on at least one of the reference datadetermined in the above mentioned first to seventh aspects.

[0048] Thirteenth Aspect

[0049] According to the thirteenth aspect of the present invention, amask blank (photomask blank) is provided and includes a resist film on asubstrate. The substrate includes at least an opaque layer and/or aphase shifting layer having an opaque function The resist film is formedby the spin-coating method according to any one of the above mentionedfirst to eleventh aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0050]FIG. 1 is a schematic diagram showing the basic configuration of acommon spin-coating device.

[0051]FIG. 2 is a diagram showing a range of combination of the mainrotation speed and the main rotation time in a conventional method.

[0052]FIGS. 3A and 3B are diagrams for illustrating a contour map as anexample of reference data used in the spin-coating method of the presentinvention. FIG. 3A is a contour map showing distribution of the filmthickness uniformity within an effective region with change in the mainrotation speed and the main rotation time, and FIG. 3B is a contour mapshowing film thicknesses with change in the main rotation speed and themain rotation time.

[0053]FIGS. 4A and 4B are diagrams showing contour maps with change inthe resist concentration. FIG. 4A is a contour map showing distributionof the film thickness uniformity within the effective region with changein the main rotation speed and the main rotation time, and FIG. 4B is acontour map showing film thicknesses with change in the main rotationspeed and the main rotation time.

[0054]FIGS. 5A and 5B are diagrams showing contour maps with change inthe drying rotation speed. FIG. 5A is a contour map showing distributionof the film thickness uniformity within the effective region with changein the main rotation speed and the main rotation time, and FIG. 5B is acontour map showing film thicknesses with change in the main rotationspeed and the main rotation time.

[0055]FIGS. 6A and 6B are diagrams showing contour maps with change inthe drying rotation speed. FIG. 6A is a contour map showing distributionof the film thickness uniformity within the effective region with changein the main rotation speed and the main rotation time, and FIG. 6B is acontour map showing film thicknesses with change in the main rotationspeed and the main rotation time.

[0056]FIGS. 7A and 7B are diagrams showing contour maps with change inthe drying rotation speed. FIG. 7A is a contour map showing distributionof the film thickness uniformity within the effective region with changein the main rotation speed and the main rotation time, and FIG. 7B is acontour map showing film thicknesses with change in the main rotationspeed and the main rotation time.

[0057]FIGS. 8A and 8B are diagrams showing contour maps with change inthe drying rotation speed. FIG. 8A is a contour map showing distributionof the film thickness uniformity within the effective region with changein the main rotation speed and the main rotation time, and FIG. 8B is acontour map showing film thicknesses with change in the main rotationspeed and the main rotation time.

[0058]FIG. 9 is a diagram showing the relationship between the resistfilm thickness and the resist concentration.

[0059]FIG. 10 is a diagram showing the relationship between the filmthickness uniformity within the effective region and the drying rotationspeed.

[0060]FIG. 11 is a schematic diagram for illustrating an effectiveregion and the like arranged on a substrate.

[0061]FIGS. 12A and 12B are schematic diagrams for illustratingeffective regions in the case of square-like (square or rectangular)substrates.

[0062]FIG. 13 is a diagram for illustrating a contour map as an exampleof reference data used in the spin-coating method according to anembodiment of the present invention, and is a contour map showingdistribution of the film thickness uniformity within the effectiveregion with change in the main rotation speed and the main rotationtime.

[0063]FIG. 14 is a diagram for illustrating a contour map as an exampleof reference data used in the spin-coating method according to anembodiment of the present invention, and is a contour map showing filmthicknesses with change in the main rotation speed and the main rotationtime.

[0064]FIG. 15 is a diagram showing the relationship between the filmthickness uniformity within the effective region and the drying rotationspeed according to an embodiment of the present invention.

[0065]FIG. 16 is a diagram showing the relationship between the resistfilm thickness and the resist concentration in an embodiment of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] Some aspects of the present invention will be described below indetail with reference to application of resist solution as an example.The present invention is applied to a specific resist spin-coatingmethod. The resist spin-coating method includes a uniforming (evening orflatting) step of dispensing a resist solution on a substrate androtating the substrate at a predetermined main rotation speed for apredetermined main rotation time, so as to primarily make the resistfilm thickness uniform, and a drying step of rotating the substrate at apredetermined drying rotation speed for a predetermined drying rotationtime after the uniforming step, so as to primarily dry the uniformresist film. Here, in general, a lower limit value of a drying rotationtime refers to the time that elapsed before the resist film iscompletely dried.

[0067] In the spin-coating method according to the first aspect of thepresent invention, reference data A is determined. When the referencedata A is determined, in the above mentioned specific resistspin-coating method, the concentration (viscosity) of the resistsolution is fixed at an arbitrary concentration (for example, aconcentration of a commercially available resist solution), and inaddition, the drying rotation speed in the drying step is fixed at anarbitrary rotation speed (for example, 50 to 300 rpm). Under thiscondition, a plurality of samples are prepared by being coated with theresist solution under a plurality of conditions resulting fromindependent, stepwise change in parameters in uniforming step while theparameters are the main rotation speed and the main rotation time. Theresist film thicknesses of each sample are measured at a plurality ofpoints within a desirably specified effective region in the substrate,and film thickness uniformity within an effective region is determinedfrom results of film thickness distribution [range (maximum minusminimum) value or standard deviation value], within the effective region(critical area) of the measurment. The relationship is therebydetermined between the condition of combination of the main rotationspeed and the main rotation time of each sample and the film thicknessuniformity within the effective region of each sample, and thisrelationship is specified to be the reference data A. Here, filmthickness uniformity within the effective region refers to a differencebetween a maximum value and a minimum value, or a standard deviation, ofthe film thicknesses in the film thickness distribution [range (maximumminus minimum) value or standard deviation value], within the effectiveregion (critical area) of the measurment.

[0068] Examples of the above mentioned reference data A include, forexample, a condition (point) of combination of the main rotation speedand the main rotation time, raw data that is recorded data of the filmthickness uniformity within the effective region corresponding to eachcondition (point) of combination without being processed (in addition,data of a mean value of the thicknesses corresponding to each condition(point) combination, a material visually representing the film thicknessuniformity within the effective region resulting from processing of thisraw data, a material in which the above mentioned raw data is stored inmemory device, and a material visually representing the film thicknessuniformity within the effective region resulting from processing of theraw data stored in memory device.

[0069] A contour map (the second aspect) as an example of the referencedata A will be described below. Explanation will be made below withreference to the case where a positive electron beam resist ZEP7000(manufactured by Zeon Corporation) is used. However, needless to say,the present invention can be applied to other resist species. Thecontour map will be described as a specific example of data processing.However, needless to say, the present invention can also be applied tothe case where the bird's eye view is used to make the film thicknessuniformity within the effective region and the mean film thickness intothree-dimensional, schematic forms.

[0070] For example, as shown in FIG. 3A, the resist concentration isfixed at 5.2%, and the drying rotation speed is fixed at 300 rpm. Underthis condition, the rotation speed of a substrate 6 inches (1 inch=25.4mm) square (152.4 mm×152.4 mm) is stepwise changed within the range of900 to 1,800 rpm in 150 rpm intervals (seven conditions). The rotationtime is stepwise changed within the range of 4 to 16 seconds in 2seconds intervals (seven conditions). The resist solution is appliedunder 49 (=7×7) conditions resulting from combination of the abovementioned conditions, and a baking treatment after coating is performedat 220° C. for 10 minutes with a heat treatment device, e.g. a hotplate, so as to prepare 49 substrates. Subsequently, regarding eachsubstrate, the film thicknesses of the resist film are measured with aspectroscopic reflection type thicknessmeter (AFT6100M manufactured byNanometrics Japan LTD.) at 121 (=11×11) points evenly arranged all overthe effective range (132 mm×132 mm) on the substrate (refer to FIG. 11),and thereby, film thickness distribution [range (maximum minus minimum)value or standard deviation value], within the effective region(critical area) of the measurment (film thickness data at individualmeasurement points) is determined. Film thickness uniformity within theeffective region is determined based on results of film thicknessdistribution [range (maximum minus minimum) value or standard deviationvalue], within the effective region (critical area) of the measurmentdata. Here, the film thickness uniformity within the effective region isdetermined from the difference between a maximum value and a minimumvalue of the film thicknesses. A mean value of the film thicknessesmeasured at 121 points are calculated so as to determine the mean resistfilm thickness for later use.

[0071] The data of these main rotation speed, main rotation time, filmthickness uniformity within the effective region and mean resist filmthickness are stored in a data memory device.

[0072] Data processing is performed in order to visually representingthe relationship among the main rotation speed, main rotation time andthe film thickness uniformity within the effective region, as describedbelow.

[0073] The film thickness uniformity within the effective region isplotted at a proper position in a graph having the horizontal axisindicating the main rotation speed and the vertical axis indicating themain rotation time. Virtual film thickness uniformity within theeffective region data is allocated based on the plotted film thicknessuniformity within the effective region data in the horizontal axisdirection, the vertical axis direction and both diagonal directions.

[0074] With respect to this allocated virtual film thickness uniformitywithin the effective region data, points corresponding to stepwisesetting film thickness uniformity within the effective region (18 stagesof 30 angstroms, 40 angstroms, 50 angstroms and the like up to 200angstroms) within the range of 20 to 200 angstroms in 10 angstromsintervals are determined (allocated), and points corresponding to thesame film thickness uniformity within the effective region are bonded bya contour line so as to prepare a contour map. The above mentionedcontour map can be prepared by data processing (software processing) ofthe date stored in the data memory device.

[0075] The range of the main rotation speed, main rotation time and thefilm thickness uniformity within the effective region, described above,can be appropriately adjusted, and preferably, the above mentionedinterval is reduced to the extent that the level of the film thicknessuniformity within the effective region can be precisely judged.Preferably, the range of the stepwise change in each of the abovementioned main rotation speed and main rotation time is increased to theextent that the tendency of the change in the film thickness uniformitywithin the effective region can be grasped, and the range of excellentfilm thickness uniformity within the effective region can be grasped.

[0076] When a substrate is coated with resist solution in practice, acondition I of combination of the main rotation speed and the mainrotation time is determined from the above mentioned reference data A orthe above mentioned contour map or bird's eye view in order to achievedesirably specified film thickness uniformity within the effectiveregion, and resist-coating is performed in accordance with results ofcondition I of combination. For example, the resist-coating can beperformed under a condition in an optimum region exhibiting maximum (thebest) film thickness uniformity within the effective region of 30 to 40angstroms, or at a region exhibiting high film thickness uniformitywithin the effective region of 40 to 50 angstroms shown in FIG. 3A. Inthis case, the resist-coating can be performed under a condition capableof achieving desirably specified film thickness uniformity within theeffective region. However, a desirably specified film thickness is notalways achieved.

[0077] In the example described above, the reference data A isvisualized by preparing the contour map of the film thickness uniformitywithin the effective region. However, the reference data A may bevisualized in such a manner that the value of the film thicknessuniformity within the effective region continuously varies in eachdirection instead of stepwise setting of the range of film thicknessuniformity within the effective region. Known examples of suchvisualization include a variable-density treatment with a gray scale anda continuation treatment using change in color (pseudo-color). The dataof the above mentioned virtual film thickness uniformity within theeffective region can be allocated in two directions of the horizontaldirection and the vertical direction, or in one diagonal direction,although the precision is reduced. Furthermore, the condition I ofcombination of the main rotation speed and the main rotation time canalso be determined directly from the reference data A or through thesoftware processing in order to achieve desirably specified filmthickness uniformity within the effective region.

[0078]FIG. 3B is a diagram of a contour map of a coating film thicknessdetermined in a manner similar to that in FIG. 3A. The mean resist filmthickness determined in the above mentioned example is plotted at aproper position in a graph having the horizontal axis indicating themain rotation speed and the vertical axis indicating the main rotationtime. For details, the contour map of the mean resist-coating filmthickness is determined as described below.

[0079] The mean resist film thickness determined in the above mentionedexample is plotted at a proper position in a graph having the horizontalaxis indicating the main rotation speed and the vertical axis indicatingthe main rotation time, based on the above mentioned reference data A.Virtual mean resist film thickness data is allocated based on theplotted mean resist film thickness data in the horizontal axisdirection, the vertical axis direction and a diagonal direction in whichthe mean film thickness exhibits a decreasing or increasing tendency.

[0080] With respect to this allocated virtual mean resist film thicknessdata, points corresponding to stepwise setting mean resist filmthickness (11 stages of 2,000 angstroms, 2,500 angstroms and the like upto 7,500 angstroms) within the range of 2,000 to 7,500 angstroms In 500angstroms intervals are determined (allocated), and points correspondingto the same resist film thickness are bonded by a contour line so as toprepare a contour map of the mean resist film thickness (FIG. 3B).

[0081] Under the condition in the optimum region exhibiting filmthickness uniformity within the effective region of 30 to 40 angstromsshown in FIG. 3A, a coating having a film thickness within the range ofabout 3,500 to 4,700 angstroms can be applied (FIG. 3B). Likewise, underthe condition in the region exhibiting film thickness uniformity withinthe effective region of 41 to 50 angstroms shown in FIG. 3A, a coatinghaving a film thickness within the range of about 3,300 to 4,800angstroms can be applied (FIG. 3B). Consequently, as described above,when a desirably specified film thickness is within these film thicknessrange, resist-coating can be performed at these conditions.

[0082] In the above mentioned contour map of the mean resist filmthickness, the range of the main rotation speed, main rotation time andthe mean resist film thickness can be appropriately adjusted in a mannersimilar to that in the above description. It is preferable to use theabove mentioned contour map of the mean resist film thickness, becausethe amount of information is increased. For example, the stability ofthe coating film thickness and the like is made clear relative tofluctuations in the main rotation speed and the main rotation time.

[0083] In the spin-coating method according to the third aspect of thepresent invention, a plurality of reference data A according to theabove mentioned first aspect or contour maps or bird's eye viewsaccording to the above mentioned second aspect are determined based onstepwise change (at least two stages) in the concentration (viscosity)of the resist solution. The optimum condition II of concentration(viscosity) of the resist solution is determined among the groupconsisting of the plural reference data A, the group consisting of theplural contour maps or the group consisting of the plural bird's eyeviews, and resist-coating is performed in accordance with results ofcondition II of concentration (viscosity) of the resist solution. Thatis, the spin-coating method according to the third aspect is a methodfor optimizing the concentration of the resist solution through the useof the reference data A according to the above mentioned first aspect orthe contour maps or bird's eye views according to the above mentionedsecond aspect.

[0084] In the third aspect, first, for example, a resist concentrationcapable of providing a region in which the film thickness uniformitywithin the effective region is at a maximum and a contour mapcorresponding to that are selected among the above mentioned group ofplural contour maps. Resist-coating is performed under a condition inthe optimum region in which the film thickness uniformity within theeffective region is at a maximum in the selected contour map.

[0085] Specifically, for example, as shown in FIG. 4A, the resistconcentration is changed to 4.7%, and the drying rotation speed is fixedat 300 rpm. In a manner similar to that in the above description, acontour map is determined with respect to a substrate 6 inches square.When the resist concentration is 4.7%, film thickness uniformity withinthe effective region of 20 to 30 angstroms or less can be achieved, asis clear from FIG. 4A. Consequently, it is clear that the film thicknessuniformity within the effective region can be improved compared with thefilm thickness uniformity within the effective region of 30 to 40angstroms or less in the case where the resist concentration is 5.2%shown in FIG. 3A. However, for example, when the resist concentration is4.7%, the film thickness is limited to within the range of about 2,800to 3,800 angstroms in order to apply the resist solution while the filmthickness uniformity within the effective region is within the range of20 to 30 angstroms or less. Therefore, a condition of combination of themain rotation speed and the main rotation time for achieving a desirablyspecified mean resist film thickness and a condition of combination ofthe main rotation speed and the main rotation time for achieving adesirably specified film thickness uniformity within the effectiveregion may not agree with each other in practice.

[0086] In such a case, a method shown below can be adopted, for example.

[0087] In the third aspect, second, for example, selection of a contourmap is performed among the above mentioned group of the plural contourmaps, so that the selected contour map can provide a desirably specifiedresist film thickness under a condition in the optimum region in whichthe film thickness uniformity within the effective region is at amaximum or in the region in which the film thickness uniformity withinthe effective region is high. Consequently, resist-coating is performedunder a condition in which the film thickness uniformity within theeffective region of the resist film is high, and a desirably specifiedfilm thickness can be achieved.

[0088] Specifically, for example, when a desirably specified resist filmthickness is 4,000 to 4,500 angstroms, the contour map shown in FIG. 3Ais selected, and thereby, the resist film thickness of 4,000 to 4,500angstroms can be achieved under a condition in the region of the filmthickness uniformity within the effective region of 31 to 40 angstroms.When the contour map shown in FIG. 4A is selected, a resist filmthickness of 2,200 to 3,750 angstroms can be achieved under a conditionin the region of the film thickness uniformity within the effectiveregion of 31 to 40 angstroms.

[0089] In each of the above mentioned examples, the resist concentrationis simply changed in two stages. However, needles to say, a more optimumcondition may be found out by increasing the range and the number ofstages in the change.

[0090] In the third aspect, by comparing the plural contour maps in thegroup according to the third aspect, it was made clear that the relativedistribution of the film thickness uniformity within the effectiveregion had almost no tendency to change with changes in the resistconcentration. Put another way, it was made clear that no change oralmost no change occurred in the optimum condition (one point or acertain range) of the main rotation speed and the main rotation time forachieving maximum film thickness uniformity within the effective regionamong the above mentioned group of the contour maps even when the resistconcentration was changed.

[0091] For example, it can be verified from the comparison between FIG.3B and FIG. 4B that the absolute value of the mean resist film thicknessis changed when the concentration of the resist solution is changed,while it can be verified from the comparison between FIG. 3A and FIG. 4Athat the tendency of the distribution of the film thickness uniformitywithin the effective region is hardly changed relatively. That is, itcan be verified that the range of the condition of the main rotationspeed and the main rotation time for achieving maximum film thicknessuniformity within the effective region is hardly changed, while the mainrotation speed is about 1,500 to 1,650 rpm, and the main rotation timeis about 8 to 10 seconds.

[0092] Consequently, the following method is considered as a method ofsimply, reliably determining an optimum resist concentration conditionfor achieving a desirably specified resist film thickness while maximumfilm thickness uniformity within the effective region is ensured. Adistribution diagram of the film thickness uniformity within theeffective region is prepared at an arbitrary resist concentration, andthereby, a condition I of combination of the main rotation speed and themain rotation time for achieving maximum film thickness uniformitywithin the effective region is determined. Subsequently, a resistconcentration for achieving a desirably specified film thickness underresults of condition I is determined from, for example, a graph (FIG. 9)showing the relationship between the film thickness and the resistconcentration, while the graph is prepared under the condition I (thesixth aspect). The sixth aspect will be described later. In thespin-coating method according to the fourth aspect of the presentinvention, a plurality of reference data A according to the abovementioned first aspect or contour maps or bird's eye views according tothe above mentioned second aspect are determined based on stepwisechange (at least two stages) in the drying rotation speed. The conditionIII of drying rotation speed for achieving maximum film thicknessuniformity within the effective region is determined among the group ofthe plural reference data, the group of the plural contour maps or thegroup of the plural bird's eye views, and resist-coating is performed inaccordance with results of condition III of drying rotation speed. Thatis, the fourth aspect is a method for optimizing the drying rotationspeed through the use of the reference data A according to the abovementioned first aspect or the contour maps or bird's eye views accordingto the above mentioned second aspect.

[0093] Explanations will be made below with reference to a specificexample. For example, as shown in FIGS. 4A to 8A, contour maps wereprepared with respect to resist solution having a resist concentrationof 4.7% on a substrate 6 inches square in a manner similar to that inthe above description, while the drying rotation speed was changedwithin the range of 50 to 300 rpm in stages of 50 rpm (FIG. 5A), 150 rpm(FIG. 6A), 200 rpm (FIG. 7A), 250 rpm (FIG. 8A) and 300 rpm (FIG. 4A).

[0094] As is clear from the above mentioned FIGS. 4A and 6A to 8A, whenthe drying rotation speed is 150 to 300 rpm, the film thicknessuniformity within the effective region of 20 to 30 angstroms or less canbe achieved, and therefore, the film thickness uniformity within theeffective region can be improved compared with the film thicknessuniformity within the effective region of 30 to 40 angstroms in the casewhere the drying rotation speed is 50 rpm, as shown in FIG. 5A.Consequently, in the fourth aspect, first, the film thickness uniformitywithin the effective region of the resist film can be at a maximum byapplying the resist solution while the drying rotation speed is set at150 to 300 rpm in order that the film thickness uniformity within theeffective region becomes a maximum.

[0095] As is clear from FIGS. 4A, 7A and 8A, when the drying rotationspeed is 200 to 300 rpm, the optimum region is increased, and the filmthickness uniformity within the effective region is at a maximum of 20to 30 angstroms in the optimum region. When the range of the optimumregion is increased, as described above, in the case where, for example,the main rotation speed and the main rotation time fluctuate relative tosetting values in a practical coating process, the resist solution isapplied under a condition within the optimum region with a highpossibility, and therefore, exhibits stability against the fluctuations.That is, when the fluctuations in the main rotation speed and the mainrotation time remain within the optimum region, the resist-coating canbe performed within the range in which the maximum film thicknessuniformity within the effective region can be achieved. When a conditionin the midsection of the optimum region is selected, the resist solutioncan be desirably applied under a condition in the optimum region even ifthe main rotation speed and the main rotation time fluctuate to someextent. Likewise, these matters apply to fluctuations in the resistconcentration (viscosity) for achieving a desirably specified meanresist film thickness.

[0096] In the fourth aspect, second, when the above mentioned conditionIII of drying rotation speed is determined from the group of the abovementioned plural reference data in the spin-coating method according tothe fourth aspect, the condition of the drying rotation speed can beselected in order that fluctuations in the film thickness uniformitywithin the effective region becomes small and stable with respect tofluctuations of the main rotation speed and/or the main rotation time ina practical coating process relative to the setting values or withrespect to fluctuations in the resist concentration (viscosity) forachieving the desirably specified mean resist film thickness, andresist-coating can be performed in accordance with results of condition(the ninth aspect). This method is very effective with respect to aresist film having film thickness uniformity within the effective regionvery sensitive to coating conditions (the main rotation speed, the mainrotation time and the like).

[0097] As is clear from FIGS. 4A, 7A and 8A, when the drying rotationspeed is 200 to 300 rpm, the optimum region is increased while the filmthickness uniformity within the effective region is at a maximum of 20to 30 angstroms in the optimum region, or the region in which the filmthickness uniformity within the effective region is high 30 to 40angstroms is increased. That is, it is clear that, by optimization ofthe drying rotation speed, an increase can be achieved in the range ofthe film thickness when coating is performed with the resist solutionhaving the same concentration, while results of film thicknessuniformity within the effective region remains within the same range.Consequently, coatings having plural sorts of film thickness can beapplied using the resist solution having the same resist concentration(viscosity), while results of film thickness uniformity within theeffective region remains within the same range. For example, when thedrying rotation speed is 250 rpm shown in FIG. 8A, the optimum region isincreased while the film thickness uniformity within the effectiveregion is at a maximum of 20 to 30 angstroms, and coatings having pluralsorts of film thickness within the range of about 2,500 to 4,500angstroms can be applied while the film thickness uniformity within theeffective region remains within the same range of 20 to 30 angstroms, asis clear from FIG. 8B.

[0098] Consequently, in the fourth aspect, third, when the abovementioned condition III of drying rotation speed is determined from thegroup of the above mentioned plural reference data in the spin-coatingmethod according to the fourth aspect, the condition III of dryingrotation speed is selected in order that when coatings having pluralsorts of film thickness are applied using the resist solution having thesame resist concentration (viscosity), coatings having plural filmthicknesses can be applied while the film thickness uniformity withinthe effective region is within a constant range. Therefore,resist-coating can be performed to achieve a plurality of filmthicknesses in accordance with results of condition III (the tenthaspect).

[0099] In the fourth aspect, by comparing the plural contour maps in thegroup according to the fourth aspect, it was made clear that no changeor almost no change occurred in the optimum condition (range) of themain rotation speed and the main rotation time for achieving maximumfilm thickness uniformity within the effective region in each contourmap even when the drying rotation speed was changed. For example, it canbe verified from FIGS. 4A to 8A that the condition (one point or acertain range) of the main rotation speed and the main rotation time forachieving maximum film thickness uniformity within the effective region(the main rotation speed: about 1,500 to 1,650 rpm, the main rotationtime: about 8 to 10 seconds) is hardly changed.

[0100] Consequently, the following method is considered as a method ofsimply optimizing the drying rotation speed. A contour map according tothe second aspect is prepared at an arbitrary resist concentration. Acondition I of combination (one point or a certain range) of the mainrotation speed and the main rotation time for achieving maximum (best)film thickness uniformity within the effective region is determined.Subsequently, a drying rotation speed capable of achieving the maximumfilm thickness uniformity within the effective region under thecondition I can be determined from, for example, a graph (FIG. 10)showing the relationship between the film thickness uniformity withinthe effective region and the drying rotation speed, while the graph isprepared under the condition I (the fifth aspect). That is, the fifthaspect is a simple technique for optimizing the drying rotation speed.This technique does not require determination of the contour map of theresist film thickness shown in FIG. 3B, and therefore, is simple.Furthermore, this technique does not require determination of thecontour map shown in FIG. 3A indicating the distribution of the filmthickness uniformity within the effective region on a drying rotationspeed basis, and therefore, is simple.

[0101] In the fifth aspect, a plurality of samples are prepared by beingcoated with the resist solution under a plurality of conditionsresulting from stepwise change in the drying rotation speed in thedrying step and under the condition fixed at the condition I of the mainrotation speed and the main rotation time determined according to thefirst aspect. The resist film thicknesses of each sample are measured ata plurality of points within a desirably specified effective region inthe substrate, and film thickness uniformity within the effective regionis determined from results of film thickness distribution [range(maximum minus minimum) value or standard deviation value], within theeffective region (critical area) of the measurment. The relationship isthereby determined between the drying rotation speed of each sample andthe film thickness uniformity within the effective region of eachsample, and this relationship is specified to be reference data B. Acondition IV of the drying rotation speed for achieving maximum filmthickness uniformity within the effective region is determined based onthe above mentioned reference data B, and resist-coating can beperformed in accordance with results of condition IV of the dryingrotation speed and with, in general, the condition I of the mainrotation speed and the main rotation time fixed as described above.

[0102] The sixth aspect takes advantage of the tendency of the relativefilm thickness distribution [range (maximum minus minimum) value orstandard deviation value], within the effective region (critical area)of the measurment to hardly change with the change in the resistconcentration, as described above. That is, the sixth aspect is a methodfor simply, reliably determining an optimum coating condition (a mainrotation speed, a main rotation time and a resist concentration) forachieving a desirably specified resist film thickness without dependingon trial-and-error methods by taking advantage of the fact that theoptimum condition (one point or a certain range) of the main rotationspeed and the main rotation time for achieving maximum film thicknessuniformity within the effective region in the group of contour maps isnot changed or is hardly changed even when the resist concentration ischanged.

[0103] That is, since the main rotation condition for increasing thefilm thickness uniformity within the effective region is not changedeven when the resist concentration (viscosity) is changed, this mainrotation condition for increasing the film thickness uniformity withinthe effective region is fixed. Subsequently, the resist concentration(viscosity) is changed in order to achieve a predetermined filmthickness, and thereby, the resist concentration (viscosity) capable ofachieving maximum film thickness uniformity within the effective regionand a desirably specified film thickness can be univocally determined.Therefore, the optimization of the resist concentration can be achieved.

[0104] Conventionally, since such a method for optimizing a resistconcentration was not established, an optimum condition, e.g. a mainrotation speed condition, was determined by trial and error at a givenresist concentration. When the resist concentration was changed, theoptimum condition, e.g. a main rotation speed condition, was determinedby trial and error with the changed resist concentration. This isbecause the optimum main rotation speed condition was believed to changeas the resist concentration was changed.

[0105] In the sixth aspect, the reference data A according to the abovementioned first aspect or the contour map or bird's eye view accordingto the above mentioned second aspect is prepared at a specific resistconcentration. A condition I of combination of the main rotation speedand the main rotation time for achieving maximum film thicknessuniformity within the effective region is determined. Subsequently, aresist concentration capable of achieving a desirably specified resistfilm thickness under the condition I can be determined from, forexample, a graph (FIG. 9) showing the relationship between the filmthickness and the resist concentration, while the graph is preparedunder the condition I.

[0106] That is, in the sixth aspect, a plurality of samples are preparedby being coated with the resist solution under a plurality of conditionsresulting from stepwise change in the concentration (viscosity) of theresist solution and under the condition fixed at the condition I of themain rotation speed and the main rotation time determined according tothe above mentioned first aspect. The resist film thicknesses of eachsample are measured at a plurality of points within a desirablyspecified effective region in the substrate, and a mean value of resultsof resist film thicknesses is determined. The relationship is therebydetermined between the concentration (viscosity) of the resist solutionof each sample and the mean value of the resist film thicknesses of eachsample, and this relationship is specified to be reference data C. Acondition V of concentration (viscosity) of the resist solution forachieving a desirably specified mean resist film thickness is determinedbased on the above mentioned reference data C, and resist-coating isperformed in accordance with results of condition of V of concentration(viscosity) of the resist solution and with, in general, the condition Iof the main rotation speed and the main rotation time fixed as describedabove.

[0107] In the seventh aspect, the technique according to the abovementioned sixth aspect is performed under the condition in which thedrying rotation speed is optimized by the simple optimization techniquefor the drying rotation speed according to the fifth aspect describedabove.

[0108] The eighth aspect relates to a determination procedure of themain rotation condition, the drying rotation condition and the resistconcentration condition. The reference data A according to the abovementioned first aspect or the contour map or bird's eye view accordingto the above mentioned second aspect is prepared at an arbitrary resistconcentration. A condition I of combination of the main rotation speedand the main rotation time for achieving maximum film thicknessuniformity within the effective region is determined (the first orsecond aspect).

[0109] The condition IV of the drying rotation speed capable ofachieving maximum film thickness uniformity within the effective regionunder the above mentioned condition I is determined from, for example, agraph (FIG. 10) showing the relationship between the film thicknessuniformity within the effective region and the drying rotation speed,while the graph is prepared under the condition I (the fifth aspect).

[0110] Under a condition fixed at the optimum main rotation condition Iand at the optimum drying rotation condition IV, a resist concentrationcondition V′ for achieving a desirably specified resist film thicknessis determined from, for example, a graph (FIG. 9) showing therelationship between the film thickness and the resist concentration,while the graph is prepared under the condition I (the seventh aspect).

[0111] As described above, the resist concentration is finallydetermined in order to achieve a desirably specified resist filmthickness.

[0112] According to the eighth aspect, the main rotation condition, thedrying rotation condition and the resist concentration condition can beunivocally determined in order to achieve maximum film thicknessuniformity within the effective region and a desirably specified filmthickness.

[0113] That is, in the eighth aspect, the main rotation speed and themain rotation time are selectively fixed at the condition I by thedetermination method for the main rotation condition according to thefirst aspect or the second aspect. The drying rotation speed isselectively fixed at the condition IV by the determination method forthe drying rotation condition according to the fifth aspect. Theconcentration (viscosity) of the resist solution is selectively fixed atthe condition V′ by the determination method for the concentration(viscosity) of the resist solution according to the seventh aspect.Subsequently, resist-coating is performed in accordance with thecondition I, condition IV and condition V′.

[0114] Eleventh Aspect

[0115] The eleventh aspect is specified because effects and necessity ofthe present invention are especially significant when the substrate is asquare-like (square or rectangular) substrate. Examples of square-like(square or rectangular) substrates include quadrangular substrates, forexample, a square and a rectangle.

[0116] The present invention is not limited to the case where resistsolution is applied to a substrate including a thin film, e.g. an opaquelayer and/or a phase shifting layer having an opaque function, but alsoinclude the case where coating is applied to form a resist bottomanti-reflective coating, a resist top anti-reflective layer, a resisttop protective film, a conductive film, other coating films, anarbitrary combination thereof or the like. Furthermore, the presentinvention include the case where coating is applied to form a resistfilm, a resist bottom anti-reflective coating, a resist topanti-reflective layer, a resist top protective film, a conductive film,other coating films, an arbitrary combination thereof or the like on asubstrate including no thin film.

[0117] Twelfth Aspect

[0118] The twelfth aspect is a determination method for a resist-coatingcondition in which the resist-coating condition is determined based onat least one of reference data determined in the resist spin-coatingmethods according to the above mentioned first to seventh aspects. Here,examples of the resist-coating condition include, for example, a mainrotation speed, a main rotation time, a drying rotation speed, a dryingrotation time, a resist concentration, a sort of resist solution and asolvent.

[0119] Thirteenth Aspect

[0120] The thirteenth aspect is a mask blank (photomask blank) includinga resist film, a resist bottom anti-reflective coating, a resist topanti-reflective layer, a resist top protective film, a conductive film,other coating films, an arbitrary combination thereof or the likearranged on a substrate including at least an opaque layer and/or aphase shifting layer having an opaque function by the resistspin-coating method according to any one of the above mentioned first totenth aspects.

[0121] Embodiments

[0122] Resist-coating was performed using 8.5% solution of FEP171(manufactured by FUJIFILM Arch Co., Ltd.) in accordance with the abovementioned eighth aspect. FEP171 was a positive electron beam resist, anda solvent of the solution was a mixed solution of PGMEA (propyleneglycol monomethyl ether acetate) and PGME (propylene glycol monomethylether) at a ratio of 8 to 2.

[0123] Specifically, 8.5% solution of FEP171 was used, and the dryingrotation speed was fixed at 300 rpm. A substrate 6 inches square (152.4mm square) was used, and the substrate had a thickness of 0.25 inches(6.35 mm). The main rotation speed was stepwise changed within the rangeof 750 to 1,750 rpm in 250 rpm intervals (5 conditions), and the mainrotation time was stepwise changed within the range of 1 to 5 seconds in1 second intervals (5 conditions). Regarding 25 (=5×5) conditionsresulting from combination of the above mentioned conditions, 25 samplesubstrates coated with FEP171 were prepared. The film thicknesses ofeach sample were measured at 121 (=11×11) points uniformly located allover an effective region of 132 mm by 132 mm in the midsection of thesubstrate by using a spectroscopic reflection type thicknessmeter(AFT6100M manufactured by Nanometrics Japan LTD.), and thereby, filmthickness distribution [range (maximum minus minimum) value or standarddeviation value], within the effective region (critical area) of themeasurment (film thickness data at individual measurement points) wasdetermined.

[0124] Regarding each sample substrate, film thickness uniformity withinthe effective region was determined as a difference between the maximumvalue and the minimum value of the film thicknesses based on results offilm thickness distribution data (reference data A) within the effectiveregion (critical area) of the measurment. The mean value was calculatedfrom film thicknesses measured at the above mentioned 121 points, andthereby, the mean film thickness of each sample substrate wasdetermined.

[0125] The data with respect to the above mentioned combination of themain rotation speed and the main rotation time, the film thicknessuniformity within the effective region and the mean film thickness werestored in data memory device. Data processing was performed inaccordance with the above mentioned technique in order to visuallyrepresent the relationship between the combination of the main rotationspeed and the main rotation time and the film thickness uniformitywithin the effective region and the relationship between the combinationof the main rotation speed and the main rotation time and the mean filmthickness.

[0126] With respect to the processed data of the relationship betweenthe combination of the main rotation speed and the main rotation timeand the film thickness uniformity within the effective region, pointscorresponding to stepwise setting film thickness uniformity within theeffective region (7 stages of 50 angstroms, 60 angstroms, 70 angstromsand the like up to 100 angstroms and 100 angstroms or more) weredetermined (allocated) within the range of 40 to 100 angstroms in 10angstroms intervals, and points corresponding to the same film thicknessuniformity within the effective region were bonded by a contour line soas to prepare a contour map.

[0127]FIG. 13 is a diagram showing a contour map. The film thicknessuniformity within the effective region determined as described above isplotted at a proper position in a graph having the horizontal axisindicating the main rotation speed and the vertical axis indicating themain rotation time, and the contour map was thereby determined. Theabove mentioned contour map was prepared by data processing (softwareprocessing) of the date stored in the data memory device.

[0128] A combination of the main rotation speed and the main rotationtime, capable of achieving maximum (best) film thickness uniformitywithin the effective region (that is, condition I) was determined fromthe above mentioned reference data A and the contour map. That is, themain rotation condition I was specified to be “a main rotation speed of1,500 rpm and a main rotation time of 2 seconds” because maximum filmthickness uniformity within the effective region of 40 angstroms wasachieved in the above mentioned reference data A and the contour map.

[0129]FIG. 14 is a diagram showing a contour map. With respect to theprocessed data of the relationship between the combination of the mainrotation speed and the main rotation time and the mean film thickness,points corresponding to stepwise setting mean film thicknesses in 250angstroms intervals were determined (allocated), and pointscorresponding to the same mean film thickness were bonded by a contourline so as to prepare the contour map having the vertical axisindicating the main rotation speed and the horizontal axis indicatingthe main rotation time.

[0130] A mean value of the coating film thicknesses was 6,488 angstromsunder the condition in which the maximum film thickness uniformitywithin the effective region of 40 angstroms was achieved, that is, inthe case where the main rotation speed was specified to be 1,500 rpm,and the main rotation time was specified to be 2 seconds. Consequently,a desirably specified film thickness of 5,000 angstroms, or anotherdesirably specified film thickness of 3,000 angstroms was not achieved.

[0131] Subsequently, the drying rotation speed was optimized. Asdescribed above, almost no change occurs in the condition of combinationof the main rotation speed and the main rotation time for achievingmaximum film thickness uniformity within the effective region in thecontour map representing the distribution of the film thicknessuniformity within the effective region even when the drying rotationspeed is changed. In consideration of this fact, optimization of thedrying rotation speed was performed as described below.

[0132] A plurality of sample substrates were prepared by coatingsubstrates 6 inches square having a thickness of 0.25 inches with FEP171having a resist concentration of 8.5%, while the main rotation speed wasfixed at 1,500 rpm, the main rotation time was fixed at 2 seconds, andthe drying rotation speed was stepwise changed within the range of 100to 300 rpm in 50 rpm intervals. The film thickness uniformity within theeffective region of each sample substrate was measured in a mannerdescribed above, and the relationship (graph) between the film thicknessuniformity within the effective region and the drying rotation speed wasdetermined (FIG. 15).

[0133] As is clear from FIG. 15, maximum film thickness uniformitywithin the effective region can be achieved at the drying rotation speed(drying rotation condition IV) of 250 rpm.

[0134] Subsequently, the resist concentration was optimized. Asdescribed above, almost no change occurs in the condition of combinationof the main rotation speed and the main rotation time for achievingmaximum film thickness uniformity within the effective region in thecontour map representing the distribution of the film thicknessuniformity within the effective region even when the resistconcentration is changed. Furthermore, almost no change occurs in thecondition of combination of the main rotation speed and the mainrotation time for achieving maximum film thickness uniformity within theeffective region in the contour map representing the distribution of thefilm thickness uniformity within the effective region even when thedrying rotation speed is changed. In consideration of these facts, theresist concentration was optimized as described below.

[0135] FEP171 having a resist concentration of 8.5% was diluted with amixed solution of PGMEA (propylene glycol monomethyl ether acetate) andPGME (propylene glycol monomethyl ether) at a ratio of 8 to 2. Thismixed solution was the solvent in FEP171. Ratios of the undilutedsolution (8.5%) to the amount of addition of the solvent (dilutionratios) were specified to be 10 to 0, 10 to 1, 10 to 2, 10 to 3, 10 to4, 10 to 5 and 10 to 10 (1 to 1), and therefore, diluted solutions wereprepared.

[0136] Each of the above mentioned 7 sorts of diluted solution wasapplied onto a substrate 6 inches square having a thickness of 0.25inches while a main rotation speed was fixed at 1,500 rpm, a mainrotation time was fixed at 2 seconds, and a drying rotation speed wasfixed at 250 rpm, so that a sample substrate was prepared. The mean filmthicknesses of each sample substrate were measured by the methoddescribed above, and the relationship (graph) between the mean filmthickness and the resist concentration was determined (FIG. 16).

[0137] As is clear from FIG. 16, when the dilution ratio is specified tobe 100 to 20 (that is, the resist concentration condition V′ isspecified to be about 7.08%), a desirably specified film thickness of5,000 angstroms can be achieved. When the dilution ratio is specified tobe 100 to 65 (that is, the resist concentration condition V′ isspecified to be about 5.15%), another desirably specified film thicknessof 3,000 angstroms can be achieved.

[0138] An FEP171 solution was adjusted to have a resist concentration ofabout 7.08%. Coating was performed onto a substrate 6 inches squarehaving a thickness of 0.25 inches while a main rotation speed was fixedat 1,500 rpm, a main rotation time was fixed at 2 seconds, and a dryingrotation speed was fixed at 250 rpm. A baking treatment was performedafter the coating, and therefore, a sample substrate was prepared.

[0139] Regarding the above mentioned sample substrate, the coating filmthicknesses were measured at 121 points uniformly located all over aneffective region (132 mm×132 mm) on the substrate with a spectroscopicreflection type thicknessmeter (AFT6100M manufactured by NanometricsJapan LTD.). Subsequently, the mean film thickness (a mean valuecalculated from film thickness data at individual easurement points) andfilm thickness uniformity within the effective region (a range valuecalculated from film thickness data at individual measurement points)were determined from the measurement results. Results of film thicknessuniformity within the effective region was 38 angstroms when the meanfilm thickness was 5,003 angstroms.

[0140] An FEP171 solution was adjusted to have a resist concentration ofabout 5.15%. Coating was performed onto a substrate 6 inches squarehaving a thickness of 0.25 inches while a main rotation speed was fixedat 1,500 rpm, a main rotation time was fixed at 2 seconds, and a dryingrotation speed was fixed at 250 rpm. A baking treatment was performedafter the coating, and therefore, a sample substrate was prepared.Regarding the above mentioned sample substrate, the coating filmthicknesses were measured at 121 points uniformly located all over aneffective region (132 mm×132 mm) on the substrate with a spectroscopicreflection type thicknessmeter (AFT6100M manufactured by NanometricsJapan LTD.). Subsequently, the mean film thickness (a mean valuecalculated from film thickness data at individual measurement points)and film thickness uniformity within the effective region (a range valuecalculated from film thickness data at individual measurement points)were determined from the measurement results. Results of film thicknessuniformity within the effective region was 28 angstroms when the meanfilm thickness was 3,005 angstroms.

[0141] It is also clear from the above mentioned two results that thefilm thickness uniformity within the effective region is improved withrespect to the sample having a lower resist concentration (the samplehaving a smaller mean resist film thickness).

[0142] As is clear from the above mentioned results, the condition I ofthe main rotation speed and the main rotation time is selectively fixedby the determination method for the main rotation condition according tothe first aspect or the second aspect, the condition IV of the dryingrotation speed is selectively fixed by the determination method for thedrying condition according to the fifth aspect, and the condition V′ ofconcentration of the resist solution is selectively fixed by thedetermination method for the concentration of the resist solutionaccording to the seventh aspect. Resist-coating is performed inaccordance with the condition I, condition IV and condition V′.Consequently, each condition can be univocally determined, and maximumfilm thickness uniformity within the effective region can be achieved.

[0143] The present invention is not limited to the above description. Itis needless to say that in the present invention, the above mentionedreference data A, the contour map or the bird's eye view can be preparedin consideration of the results of optimization of the resistconcentration, the drying rotation speed and the like.

[0144] It is needless to say that in the present invention, the abovementioned reference data A, the contour map or the bird's eye view canbe prepared with respect to various sorts of resist solution

[0145] The uniformity of the resist film thickness achieved by thespin-coating method is affected by the resist species, the solvent, theshape of a cup of a coating device, the amount of exhaust or the like.Consequently, when the uniformity of the resist film thickness isimproved by improvements of these conditions, coating can be performedwith film thickness uniformity within the effective region higher thanthe film thickness uniformity within the effective region exemplified inthe above description by combining these conditions with the presentinvention.

[0146] The size and the shape of the substrate are not limited to thesubstrate 6 inches square.

[0147] In the present invention, the region for measurement of theresist film is not specifically limited as long as the region is in thesubstrate. However, desirably, the measurement is performed in aneffective region because a pattern (e.g. a mask pattern and a circuitpattern) and the like is formed in that region on the substrate. Inorder to precisely prepare the contour map or the bird's eye view,desirably, measurement is performed at the maximum number of pointsspaced at regular intervals all over the effective range.

[0148] In the present invention, the resist film thickness can bemeasured using, for example, spectroscopic reflection typethicknessmeters and contact probe type thicknessmeters. Regarding themeasurement of the film thickness uniformity within the effective regionof each sample substrate of the above mentioned resist film, themeasurement was performed using these spectroscopic reflection typethicknessmeters.

[0149] In the present invention, the effective region on the substratecan be appropriately selected in accordance with requiredspecifications. For example, in the case of a photomask blank or a phaseshifting mask blank in which a substrate is a square-like (square orrectangular) substrate, a region for arrangement of a mask pattern isselected. This is because a desirably specified patterningcharacteristic (pattern dimension precision) cannot be achieved when thefilm thickness uniformity within the effective region of the resist filmexceeds a predetermined value in the region for arrangement of a maskpattern. For example, when the size of the substrate is 6 inches by 6inches, the effective region is specified to be a square of 132 mm by132 mm in the midsection of the substrate, and a mask pattern is formedtherein. When desirably specified film thickness uniformity within theeffective region must be ensured in a region for arrangement of analignment mark outside the region for arrangement of the mask pattern ora region for arrangement of an auxiliary pattern, e.g. a QA patternindicating quality assurance of the mask, an effective region ofmeasurement of the film thickness uniformity within the effective regionof each sample substrate is specified in accordance with those regions.

[0150] When the region for arrangement of the mask pattern is in theshape of a square, the above mentioned desirably specified effectiveregion is specified to be in the shape of a quadrangle (the shapesimilar to the region for arrangement of the mask pattern, the shapesimilar to the square-like (square or rectangular) substrate and thelike), as shown in FIG. 12A. On the other hand, when the region forarrangement of the mask pattern is in the shape of a rectangle, thedesirably specified effective region is specified to be in the shape ofa cross adjusted to exclude the four corner portions, as shown in FIG.12B.

[0151] In general, when change occurs in the desirably specifiedeffective region for measuring the film thickness distribution withinthe effective region (critical area) of the measurment (film thicknessuniformity within an effective region) of the resist film, change alsooccurs in the film thickness distribution within the effective region(critical area) of the measurment, and therefore, the film thicknessdistribution within the effective region (critical area) of themeasurment (film thickness uniformity within an effective region) mustbe measured on a required specification basis.

[0152] In the present invention, predetermined film thickness uniformitywithin the effective region can be appropriately selected in accordancewith a required specification. The lower limit value of the filmthickness uniformity within the effective region is restricted by aresist species, a desirably specified film thickness, a resist-coatingdevice, limits of measurement of the film thickness distribution withinthe effective region (critical area) of the measurment (film thicknessuniformity within the effective region) and the like, and therefore, isappropriately selected in accordance therewith.

[0153] The mask blank referred to in the present invention includes aphotomask blank and a phase shifting mask blank. The mask blank referredto in the present invention includes a blank with a resist film, as wellas a mask blank including a resist film, a resist bottom anti-reflectivecoating, a resist top anti-reflective layer, a resist top protectivefilm, a conductive film, other coating film, an arbitrary combinationthereof or the like, and a blank before arrangement of these films. Themask referred to in the present invention includes a photomask and aphase shifting mask. The mask referred to in the present inventionincludes a reticle.

[0154] The present invention includes the following modified aspects.The present invention is also applied to a spin-coating method includinga uniforming step of dispensing a coating solution on a substrate androtating the substrate at a predetermined main rotation speed for apredetermined main rotation time, so as to primarily make the coatingfilm thickness uniform, and a drying step of rotating the substrate at apredetermined drying rotation speed for a predetermined drying rotationtime after the uniforming step, so as to primarily dry the uniformcoating film.

[0155] First Modified Aspect

[0156] The first modified aspect will be described below. In the abovementioned spin-coating method, a plurality of samples are prepared bybeing coated with the coating solution under a plurality of conditionsresulting from independent, stepwise change in parameters in theuniforming step, while the parameters are the main rotation speed andthe main rotation time, and under the condition in which theconcentration (viscosity) of the coating solution is fixed at anarbitrary concentration, and the drying rotation speed in the dryingstep is fixed at an arbitrary rotation speed. The coating filmthicknesses of each sample are measured at a plurality of points withina desirably specified effective region in the substrate, and filmthickness uniformity within the effective region is determined fromresults of film thickness distribution [range (maximum minus minimum)value or standard deviation value], within the effective region(critical area) of the measurment. The relationship is therebydetermined between the condition of combination of the main rotationspeed and the main rotation time of each sample and the film thicknessuniformity within the effective region of each sample, and thisrelationship is specified to be reference data A. A condition I ofcombination of the main rotation speed and the main rotation time forachieving desirably specified film thickness uniformity within theeffective region is determined based on the reference data A, andapplication of the coating solution is performed in accordance withresults of condition I of combination of the main rotation speed and themain rotation time.

[0157] Second Modified Aspect

[0158] In the second modified aspect, the reference data A is a contourmap in which the vertical axis indicates the main rotation speed, thehorizontal axis indicates the main rotation time, and pointscorresponding to the same film thickness uniformity within the effectiveregion are bonded by a contour line, or a bird's eye view drawn bypoint-plotting while the X axis, the Y axis and the Z axis indicate themain rotation speed, the main rotation time and the film thicknessuniformity within the effective region, respectively.

[0159] Third Modified Aspect

[0160] In the third modified aspect, a plurality of reference data Aaccording to the above mentioned first modified aspect or contour mapsor bird's eye views according to the above mentioned second modifiedaspect are determined based on stepwise change in the concentration(viscosity) of the coating solution, the condition II of concentration(viscosity) of the coating solution for achieving maximum film thicknessuniformity within the effective region is determined among the groupconsisting of the plural reference data A, the group consisting of theplural contour maps or the group consisting of the plural bird's eyeviews, and application of the coating solution is performed inaccordance with results of condition II of concentration (viscosity) ofthe coating solution.

[0161] Fourth Modified Aspect

[0162] In the fourth modified aspect, a plurality of reference data Aaccording to the above mentioned first modified aspect or contour mapsor bird's eye views according to the above mentioned second modifiedaspect are determined based on stepwise change in the drying rotationspeed in the drying step while the concentration (viscosity) of thecoating solution is fixed at an arbitrary concentration, the conditionIII of drying rotation speed for achieving maximum film thicknessuniformity within the effective region is determined among the groupconsisting of the plural reference data A, the group consisting of theplural contour maps or the group consisting of the plural bird's eyeviews, and application of the coating solution is performed inaccordance with results of condition III of drying rotation speed.

[0163] Fifth Modified Aspect

[0164] In the fifth modified aspect, a plurality of samples are preparedby being coated with the coating solution under a plurality ofconditions resulting from stepwise change in the drying rotation speedin the drying step and under the condition in which the main rotationspeed and the main rotation time in the uniforming step are fixed at thecondition I of the main rotation speed and the main rotation timedetermined according to the above mentioned first modified aspect. Thecoating film thicknesses of each sample are measured at a plurality ofpoints within a desirably specified effective region in the substrate,and film thickness uniformity within the effectivbe region is determinedfrom results of film thickness distribution [range (maximum minusminimum) value or standard deviation value], within the effective region(critical area) of the measurment. The relationship is therebydetermined between the drying rotation speed of each sample and the filmthickness uniformity within the effective region of each sample, andthis relationship is specified to be reference data B. A condition IV ofthe drying rotation speed for achieving maximum (best) film thicknessuniformity within the effective region is determined based on thereference data B, and application of the coating solution is performedin accordance with results of condition IV of the drying rotation speed.

[0165] Sixth Modified Aspect

[0166] In the sixth modified aspect, a plurality of samples are preparedby being coated with the coating solution under a plurality ofconditions resulting from stepwise change in the concentration(viscosity) of the coating solution and under the condition in which themain rotation speed and the main rotation time in the uniforming stepare fixed at the condition I of the main rotation speed and the mainrotation time determined according to the above mentioned first modifiedaspect. The resist film thicknesses of each sample are measured at aplurality of points within a desirably specified effective region in thesubstrate, and a mean value of results of coating film thicknesses isdetermined. The relationship is thereby determined between theconcentration (viscosity) of the coating solution of each sample and themean value of the coating film thicknesses of each sample, and thisrelationship is specified to be reference data C. A condition of V ofconcentration (viscosity) of the coating solution for achieving adesirably specified mean coating film thickness is determined based onthe reference data C, and application of the coating solution isperformed in accordance with results of condition of V of concentration(viscosity) of the coating solution.

[0167] Seventh Modified Aspect

[0168] In the seventh modified aspect of the present invention, aplurality of samples are prepared by being coated with the coatingsolution under a plurality of conditions resulting from stepwise changein the concentration (viscosity) of the coating solution and under thecondition in which the main rotation speed and the main rotation time inthe uniforming step are fixed at the condition I of the main rotationspeed and the main rotation time determined according to the abovementioned first modified aspect, and the drying rotation speed in thedrying step is fixed at the condition IV of the drying rotation speeddetermined according to the above mentioned fifth modified aspect. Thecoating film thicknesses of each sample are measured at a plurality ofpoints within a desirably specified effective region in the substrate,and a mean value of results of coating film thicknesses is determined.The relationship is thereby determined between the concentration(viscosity) of the coating solution of each sample and the mean value ofthe coating film thicknesses of each sample, and this relationship isspecified to be reference data C′. A condition of V′ of concentration(viscosity) of the coating solution for achieving a desirably specifiedmean coating film thickness is determined based on the reference dataC′, and application of coating solution is performed in accordance withresults of condition of V′ of concentration (viscosity) of the coatingsolution.

[0169] Eighth Modified Aspect

[0170] In the eighth modified aspect, the main rotation speed and themain rotation time are selectively fixed at the condition I by thedetermination method for the main rotation condition according to theabove mentioned first modified aspect or the above mentioned secondmodified aspect. The drying rotation speed is selectively fixed at thecondition IV by the determination method for the drying rotationcondition according to the above mentioned fifth modified aspect. Theconcentration (viscosity) of the coating solution is selectively fixedat the condition V′ by the determination method for the concentration(viscosity) of the coating solution according to the above mentionedseventh modified aspect. Subsequently, application of the coatingsolution is performed in accordance with the condition I, condition IVand condition V′.

[0171] Ninth Modified Aspect

[0172] In the spin-coating method according to the above mentionedfourth modified aspect, the condition III of drying rotation speed isdetermined from the group consisting of the plural reference data, thegroup consisting of the plural contour maps or the group consisting ofthe plural bird's eye views. The drying rotation speed condition isselected in order that fluctuations in the film thickness uniformitywithin the effective region becomes small and stable with respect tofluctuations in the main rotation speed and/or the main rotation time ina practical coating process relative to the setting values or withrespect to fluctuations in the concentration (viscosity) of the coatingsolution for achieving the desirably specified mean coating filmthickness, and application of the coating solution is performed inaccordance with results of condition.

[0173] Tenth Modified Aspect

[0174] In the spin-coating method according to the above mentionedfourth modified aspect, the condition III of drying rotation speed isdetermined from the group consisting of the plural reference data, thegroup consisting of the plural contour maps or the group consisting ofthe plural bird's eye views. The condition III of drying rotation speedis selected in order that when plural thicknesses of coatings areapplied using a coating solution having the same concentration(viscosity), the plural thicknesses of coatings can be applied while thefilm thickness uniformity within the effective region is within aconstant range, and application of the coating films is performed inaccordance with results of condition III, so as to achieve a pluralityof thicknesses.

[0175] Eleventh Modified Aspect

[0176] In any one of the above mentioned first to tenth modifiedaspects, a square-like (square or rectangular) substrate is used as thesubstrate.

[0177] Twelfth Modified Aspect

[0178] The spin-coating condition is determined based on at least one ofthe reference data determined in the spin-coating methods according tothe above mentioned first to seventh modified aspects.

[0179] Thirteenth Modified Aspect

[0180] A mask blank is provided and includes a coating film on asubstrate. The substrate includes at least an opaque layer and/or aphase shifting layer having an opaque function. The coating film isformed by the spin-coating method according to any one of the abovementioned first to eleventh modified aspects.

[0181] Fourteenth Modified Aspect

[0182] A substrate including a coating film is provided. The coatingfilm is formed by the spin-coating method according to any one of theabove mentioned first to eleventh modified aspects.

[0183] In the above mentioned first to thirteenth modified aspects,examples of the coating film include, for example, a resist film, aresist bottom anti-reflective coating, a resist top anti-reflectivelayer, a resist top protective film, a conductive film, other coatingfilms, a film of an arbitrary combination thereof. The coating solutionis a solution for forming these coating films.

[0184] In the spin-coating method for applying resist solution or othercoating solution by spin coating through the above mentioned specificmethod, the present invention can provide a technique for optimizing amain rotation condition, a technique for optimizing a drying rotationcondition and a technique for optimizing a concentration (viscosity)condition of resist solution or other coating solution. The presentinvention can also provide a technique for reliably (univocally)determining these optimum conditions without depending ontrial-and-error methods.

[0185] The optimum condition of the resist spin-coating can be speedily,univocally determined without depending on trial-and-error methods, evenwhen any condition in the spin coating is changed, for example, a resistspecies or other coating solution is changed (including change insolvent), a desirably specified effective region (critical area) ischanged, a desirably specified film thickness is changed, and aspin-coating device (e.g. the shape of a cup and the shape of a chuck)is changed.

[0186] Regarding a predetermined resist species or other coatingsolution, a determination method for a spin-coating condition and aspin-coating method can be provided, while the methods can reliably(univocally) achieve desirably specified film thickness uniformitywithin the effective region (in particular, maximum film thicknessuniformity within the effective region) in a desirably specifiedeffective region without depending on trial-and-error methods. Inaddition, a mask blank (photomask blank) or a substrate can be providedand includes a resist film, etc., or other coating film formed by thismethod.

[0187] Regarding a predetermined resist species or other coatingsolution, a determination method for a spin-coating condition and aspin-coating method are provided, while the methods can reliably(univocally) achieve a desirably specified film thickness (mean) anddesirably specified film thickness uniformity within the effectiveregion in a desirably specified effective region without depending ontrial-and-error methods. In addition, a mask blank (photomask blank) ora substrate can be provided and includes a resist film, etc., or othercoating film formed by this method.

[0188] A determination method for a spin-coating condition and aspin-coating method can be provided, while the methods can reliablydetermine an optical spin-coating condition in accordance with thecharacteristics of a resist species or other coating solution withoutdepending on trial-and-error methods. In addition, a mask blank(photomask blank) or a substrate can be provided and includes a resistfilm, etc., or other coating film formed by this method.

[0189] Furthermore, a spin-coating method can be provided. The methodcan apply resist solution having one concentration or other coatingsolution having one concentration in such a manner that plural sorts ofdesirably specified resist film thickness or plural sorts of desirablyspecified coating film thickness can be achieved while the filmthickness uniformity within the effective region is within apredetermined range.

What is claimed is:
 1. A spin-coating method comprising: a uniforming(evening or flatting) step of dispensing a resist solution ort asubstrate and rotating said substrate at a predetermined main rotationspeed for a predetermined main rotation time, so as to primarily make aresist film thickness uniform; and a drying step of rotating saidsubstrate at a predetermined drying rotation speed for a predetermineddrying rotation time after said uniforming step, so as to primarily drysaid uniform resist film, wherein a plurality of samples are prepared bybeing coated with the resist solution under a plurality of conditionsresulting from independent, stepwise change in parameters in saiduniforming step, the parameters being said main rotation speed and saidmain rotation time, and under the condition in which the concentration(viscosity) of the resist solution is fixed at an arbitraryconcentration, and the drying rotation speed in said drying step isfixed at an arbitrary rotation speed, wherein the resist filmthicknesses of each sample are measured at a plurality of points withina desirably specified effective region (critical area) in saidsubstrate, film thickness uniformity within an effective region isdetermined from results of film thickness uniformity distribution withinthe effective region, the relationship is thereby determined between acondition of combination of the main rotation speed and the mainrotation time of each sample and the film thickness uniformity withinthe effective region on each sample, and this relationship is specifiedto be reference data A, wherein a condition I of combination of the mainrotation speed and the main rotation time for achieving desirablyspecified film thickness uniformity within the effective region isdetermined based on said reference data A, and wherein resist-coating isperformed in accordance with the condition I of combination of the mainrotation speed and the main rotation time.
 2. The spin-coating methodaccording to claim 1, wherein said reference data A is a contour map inwhich the vertical axis indicates said main rotation speed, thehorizontal axis indicates said main rotation time, and pointscorresponding to the same film thickness uniformity within the effectiveregion are connected by a contour line, or is a bird's eye view drawn bypoint-plotting where the X axis, the Y axis and the Z axis indicate saidmain rotation speed, said main rotation time and said film thicknessuniformity within the effective region, respectively.
 3. A spin-coatingmethod comprising: a uniforming (evening or flatting) step of dispensinga resist solution on a substrate and rotating said substrate at apredetermined main rotation speed for a predetermined main rotationtime, so as to primarily make the resist film thickness uniform; and adrying step of rotating said substrate at a predetermined dryingrotation speed for a predetermined drying rotation time after saiduniforming step, so as to primarily dry said uniform resist film,wherein a plurality of reference data A according to claim 1 aredetermined based on stepwise change in the concentration (viscosity) ofthe resist solution, and a condition II of concentration (viscosity) ofthe resist solution for achieving the maximum film thickness uniformitywithin the effective region is determined among a group consisting ofthe plural reference data A, and wherein resist-coating is performed inaccordance with the condition II of concentration (viscosity) of theresist solution.
 4. A spin-coating method comprising: a uniforming(evening or flatting) step of dispensing a resist solution on asubstrate and rotating said substrate at a predetermined main rotationspeed for a predetermined main rotation time, so as to primarily makethe resist film thickness uniform; and a drying step of rotating saidsubstrate at a predetermined drying rotation speed for a predetermineddrying rotation time after said uniforming step, so as to primarily drysaid uniform resist film, wherein a plurality of contour maps or bird'seye views according to claim 2 are determined based on stepwise changein the concentration (viscosity) of the resist solution, and a conditionII of concentration (viscosity) of the resist solution for achieving themaximum film thickness uniformity within the effective region isdetermined among a group consisting of the plural contour maps or agroup consisting of the plural bird's eye views, and whereinresist-coating is performed in accordance with the condition II ofconcentration (viscosity) of the resist solution.
 5. A spin-coatingmethod comprising: a uniforming (evening or flatting)step of dispensinga resist solution on a substrate and rotating said substrate at apredetermined main rotation speed for a predetermined main rotationtime, so as to primarily make the resist film thickness uniform; and adrying step of rotating said substrate at a predetermined dryingrotation speed for a predetermined drying rotation time after saiduniforming step, so as to primarily dry said uniform resist film,wherein a plurality of reference data A according to claim 1 aredetermined based on stepwise change in the drying rotation speed in saiddrying step when the concentration (viscosity) of the resist solution isfixed at an arbitrary concentration, and a condition III of dryingrotation speed for achieving the maximum film thickness uniformitywithin the effective region is determined among a group consisting ofthe plural reference data, and wherein resist-coating is performed inaccordance with the condition III of the drying rotation speed.
 6. Aspin-coating method comprising: a uniforming (evening or flatting)stepof dispensing a resist solution on a substrate and rotating saidsubstrate at a predetermined main rotation speed for a predeterminedmain rotation time, so as to primarily make the resist film thicknessuniform; and a drying step of rotating said substrate at a predetermineddrying rotation speed for a predetermined drying rotation time aftersaid uniforming step, so as to primarily dry said uniform resist film,wherein a plurality of contour maps or bird's eye views according toclaim 2 are determined based on stepwise change in the drying rotationspeed in said drying step when the concentration (viscosity) of theresist solution is fixed at an arbitrary concentration, and a conditionIII of drying rotation speed for achieving the maximum film thicknessuniformity within the effective region is determined among a groupconsisting of the contour maps or a group consisting of the bird's eyeviews, and wherein resist-coating is performed in accordance with thecondition III of drying rotation speed.
 7. A spin-coating methodcomprising: a uniforming (evening or flatting)step of dispensing aresist solution on a substrate and rotating said substrate at apredetermined main rotation speed for a predetermined main rotationtime, so as to primarily make the resist film thickness uniform; and adrying step of rotating said substrate at a predetermined dryingrotation speed for a predetermined drying rotation time after saiduniforming step, so as to primarily dry said uniform resist film,wherein a plurality of samples are prepared by being coated with theresist under a plurality of conditions resulting from stepwise change inthe drying rotation speed in said drying step and under the condition inwhich said main rotation speed and said main rotation time in saiduniforming step are fixed at the condition I of the main rotation speedand the main rotation time determined according to claim 1, wherein theresist film thicknesses of each sample are measured at a plurality ofpoints within a desirably specified effective region in said substrate,film thickness uniformity within the effective region is determined fromresults of the film thickness uniformity distribution within theeffective region, the relationship is thereby determined between thedrying rotation speed of each sample and the film thickness uniformitywithin the effective region on each sample, and this relationship isspecified to be reference data B, wherein a condition IV of dryingrotation speed for achieving the maximum film thickness uniformitywithin the effective region is determined based on said reference dataB, and wherein resist-coating is performed in accordance with thecondition IV of the drying rotation speed.
 8. A spin-coating methodcomprising: a uniforming (evening or flatting)step of dispensing aresist solution on a substrate and rotating said substrate at apredetermined main rotation speed for a predetermined main rotationtime, so as to primarily make the resist film thickness uniform; and adrying step of rotating said substrate at a predetermined dryingrotation speed for a predetermined drying rotation time after saiduniforming step, so as to primarily dry said uniform resist film,wherein a plurality of samples are prepared by being coated with theresist under a plurality of conditions resulting from stepwise change inthe concentration (viscosity) of the resist solution and under thecondition in which said main rotation speed and said main rotation timein said uniforming step are fixed at the condition I determinedaccording to claim 1, wherein the resist film thicknesses of each sampleare measured at a plurality of points within a desirably specifiedeffective region in said substrate, a mean value of results of resistfilm thicknesses measurements is determined, the relationship is therebydetermined between the concentration (viscosity) of the resist solutionof each sample and the mean value of the resist film thicknesses of eachsample, and this relationship is specified to be reference data C,wherein a condition V of concentration (viscosity) of the resistsolution for achieving a desirably specified resist film thickness meanis determined based on said reference data C, and wherein resist-coatingis performed in accordance with the condition V of concentration(viscosity) of the resist solution.
 9. A spin-coating method comprising:a uniforming (evening or flatting)step of dispensing a resist solutionon a substrate and rotating said substrate at a predetermined mainrotation speed for a predetermined main rotation time, so as toprimarily make the resist film thickness uniform; and a drying step ofrotating said substrate at a predetermined drying rotation speed for apredetermined drying rotation time after said uniforming step, so as toprimarily dry said uniform resist film, wherein a plurality of samplesare prepared by being coated with the resist under a plurality ofconditions resulting from stepwise change in the concentration(viscosity) of the resist solution and under the condition in which saidmain rotation speed and said main rotation time in said uniforming stepare fixed at the condition I of the main rotation speed and the mainrotation time determined according to claim 1, and the drying rotationspeed in said drying step is fixed at the condition IV of dryingrotation speed determined according to claim 7, wherein the resist filmthicknesses of each samples are measured at a plurality of points withina desirably specified effective region in said substrate, a mean valueof the results of resist film thicknesses measurements is determined,the relationship is thereby determined between the concentration(viscosity) of the resist solution of each sample and the mean value ofthe resist film thicknesses of each sample, and this relationship isspecified to be reference data C′, wherein a condition V′ ofconcentration (viscosity) of the resist solution for achieving adesirably specified resist film thickness mean is determined based onsaid reference data C′, and wherein resist-coating is performed inaccordance with the condition V′ of concentration (viscosity) of theresist solution.
 10. A spin-coating method comprising: a uniforming(evening or flatting)step of dispensing a resist solution on a substrateand rotating said substrate at a predetermined main rotation speed for apredetermined main rotation time, so as to primarily make the resistfilm thickness uniform; and a drying step of rotating said substrate ata predetermined drying rotation speed for a predetermined dryingrotation time after said uniforming step, so as to primarily dry saiduniform resist film, wherein the main rotation speed and the mainrotation time are selectively fixed at the condition I by thedetermination method for the main rotation condition according to claim1, wherein the drying rotation speed is selectively fixed at thecondition IV by the determination method for the drying rotationcondition according to claim 7, wherein the concentration (viscosity) ofthe resist solution is selectively fixed at the condition V′ by thedetermination method for the resist concentration (viscosity) accordingto claim 9, and wherein resist-coating is performed in accordance withthe condition I, condition IV and condition V′.
 11. A spin-coatingmethod comprising: a uniforming (evening or flatting)step of dispensinga resist solution on a substrate and rotating said substrate at apredetermined main rotation speed for a predetermined main rotationtime, so as to primarily make the resist film thickness uniform; and adrying step of rotating said substrate at a predetermined dryingrotation speed for a predetermined drying rotation time after saiduniforming step, so as to primarily dry said uniform resist film,wherein the main rotation speed and the main rotation time areselectively fixed at the condition I by the determination method for themain rotation condition according to claim 2, wherein the dryingrotation speed is selectively fixed at the condition IV by thedetermination method for the drying rotation condition according toclaim 7, wherein the concentration (viscosity) of the resist solution isselectively fixed at the condition V′ by the determination method forthe resist concentration (viscosity) according to claim 9, and whereinresist-coating is performed in accordance with the condition I,condition IV and condition V′.
 12. The spin-coating method according toclaim 5, in which the condition III of drying rotation speed isdetermined from said group consisting of the plural reference data,wherein the condition of the drying rotation speed is selected in orderthat fluctuations in the film thickness uniformity distribution withinthe effective region becomes small and stable with respect tofluctuations of the main rotation speed and/or the main rotation time ina practical coating process relative to the setting values or withrespect to fluctuations in the resist concentration (viscosity) forachieving the desirably specified resist film thickness mean, andresist-coating is performed in accordance with the condition determined.13. The spin-coating method according to claim 6, in which the conditionIII of drying rotation speed is determined from said group consisting ofthe contour maps or said group consisting of the bird's eye views,wherein the condition of the drying rotation speed is selected in orderthat fluctuations in the film thickness uniformity within the effectiveregion becomes small and stable with respect to fluctuations of the mainrotation speed and/or the main rotation time in a practical coatingprocess relative to the setting values or with respect to fluctuationsin the resist concentration (viscosity) for achieving the desirablyspecified resist film thickness mean, and resist-coating is performed inaccordance with the condition determined.
 14. The spin-coating methodaccording to claim 5, in which the condition III of drying rotationspeed is determined from said group consisting of the plural referencedata, wherein the condition III of drying rotation speed is selected inorder that when plural thicknesses of coatings are applied using theresist having the fixed resist concentration (viscosity), the pluralthicknesses of coatings can be applied with maintaining the filmthickness uniformity within the effective region within a constant rangevalue, and resist-coating is performed in accordance with the conditionIII, so as to obtain a plurality of film thicknesses.
 15. Thespin-coating method according to claim 6, in which the condition III ofdrying rotation speed is determined from said group consisting of thecontour maps or said group consisting of the bird's eye views, whereinthe condition III of drying rotation speed is selected in order that,even when plural thicknesses of coatings are applied using the resisthaving the same resist concentration (viscosity), the plural thicknessesof coatings can be applied with maintaining the film thicknessuniformity within the effective region within a constant range value,and resist-coating is performed in accordance with the condition III, soas to obtain a plurality of film thicknesses.
 16. A determination methodfor a spin-coating condition, comprising the step of determining thespin-coating condition based on at least one of the reference datadetermined in the spin-coating methods according to claims 1 to
 9. 17. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 1. 18. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 3. 19. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 4. 20. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 5. 21. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 6. 22. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 7. 23. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 8. 24. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 9. 25. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim
 10. 26. Amask blank comprising a resist film on a substrate, wherein thesubstrate includes at least an opaque layer and/or a phase-shiftinglayer, or phase-shifting layer having an opaque function, and the resistfilm is formed by the spin-coating method according to claim 11.